1. Field of the Invention
This invention relates to novel meso-ionic sulfur- and selenium-containing tetrazole compounds useful in photography and to a novel intermediate useful in the preparation of said meso-ionic compounds.
2. Description of the Prior Art
Various tetrazolium compounds, i.e., quaternized tetrazoles containing a ring of one carbon and four nitrogren atoms, one of which is quaternary, are known. Though most of the tetrazolium salts prepared so far have been derived from (2H)tetrazoles, some quaternary salts of (1H)tetrazoles also have been reported. As discussed in Heterocyclic Compounds, Robert C. Elderfield, Vol. 8, pp. 55 and 62, John Wiley & Sons, Inc., New York, 1967, quaternization of 1,5-disubstituted tetrazoles occurs readily with methyl benzenesulfonate or methyl iodide to give the corresponding 4-methyl product in the quaternary salts investigated. For example, methylation of 1-methyl-5-methylthiotetrazole gave the corresponding 1,4-dimethyl-5-methylthiotetrazolium iodide. Like the tetrazolium salts, the meso-ionic tetrazole compounds previously reported have been primarily (2H)tetrazole derivatives.
The present invention is concerned with the ethylation of 1-phenyl-5-methylthiotetrazole, with the ethylation product obtained and with the products obtained upon solvolysis of the ethylation product with .sup.-SeH and .sup.-SH.